UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates atherosclerosis in mice via regulating the SMAD7/YAP1 axis.

BACKGROUND: Endothelial cell injury and dysfunction lead to cholesterol and lipid accumulation and atherosclerotic plaque formation in the arterial wall during atherosclerosis (AS) progression, Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1), a DNA methylation regulator, was strongly upregulated in atherosclerotic plaque lesions in mice. This study aimed to investigate the precise biological functions and regulatory mechanisms of UHRF1 on endothelial dysfunction during AS development. METHODS: UHRF1 levels in the atherosclerotic plaque tissues and normal arterial intima from AS patients were tested with Western blot analysis and immunohistochemistry assays. Human umbilical vein endothelial cells (HUVECs) were stimulated with oxidized low-density lipoprotein (ox-LDL) to induce an injury model and then transfected with short hairpin RNA targeting UHRF1 (sh-UHRF1). Cell proliferation, migration, apoptosis, the levels of inflammatory cytokines including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), and the protein levels adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were measured. Moreover, co-immunoprecipitation assay was used to determine the interactions between UHRF1 and DNA methyltransferases 1 (DNMT1), As well as mothers against DPP homolog 7 (SMAD7) and yes-associated protein 1 (YAP1). SMAD7 promoter methylation was examined with methylation-specific PCR. In addition, we established an AS mouse model to determine the in vivo effects of UHRF1 on AS progression. RESULTS: UHRF1 was upregulated in atherosclerotic plaque tissues and ox-LDL-treated HUVECs. UHRF1 knockdown mitigated ox-LDL-induced proliferation and migration inhibition, apoptosis and the production of TNF-α, IL-6, VCAM-1, and ICAM-1 in HUVECs. Mechanistically, UHRF1 promoted DNMT1-mediated SMAD7 promoter methylation and inhibited its expression. SMAD7 knockdown abolished the protective effects of UHRF1 knockdown on ox-LDL-induced HUVEC injury. Moreover, SMAD7 interacted with YAP1 and inhibited YAP1 expression by promoting YAP1 protein ubiquitination-independent degradation in HUVECs. YAP1 overexpression abrogated SMAD7 overexpression-mediated protective effects on ox-LDL-induced HUVEC injury. Finally, UHRF1 knockdown alleviated atherosclerotic plaque deposition and arterial lesions in AS mice. CONCLUSION: UHRF1 inhibition mitigates vascular endothelial cell injury and ameliorates AS progression in mice by regulating the SMAD7/YAP1 axis.

Mir-195-5p targets Smad7 regulation of the Wnt/ß-catenin pathway to promote osteogenic differentiation of vascular smooth muscle cells.

In this study, we sought to investigate the mechanisms of action of miR-195-5p in the osteogenic differentiation of vascular smooth muscle cells (VSMCs), and thereby provide novel insights and a reference for the targeted therapy of arterial media calcification. VSMC differentiation was induced using sodium ß-glycerophosphate, and we investigated the effects of transfecting cells with miR-195-5p mimics, vectors overexpressing Smad7, and the Wnt/ß-catenin pathway inhibitor (KYA1797K) on VSMC differentiation by determining cell viability and apoptosis, and the mRNA and protein expression of factors associated with osteogenic differentiation and the Wnt/ß-catenin pathway. The results revealed that miR-195-5p mimics enhanced the osteogenic differentiation of VSMCs induced by ß-glycerophosphate, whereas the overexpression of Smad7 reversed this phenomenon. In addition, KYA1797K was found to promote the effects of Smad7 overexpression. In conclusion, by targeting, Smad7, miR-195-5p promotes the Wnt/ß-catenin pathway. and thus the osteogenic differentiation of VSMCs. These findings will provide a reference for elucidating the mechanisms whereby miR-195-5p regulates osteogenic differentiation.

SIRT1 activation ameliorates rhesus monkey liver fibrosis by inhibiting the TGF-ß/smad signaling pathway.

TGF-ß/Smad signaling pathway plays an important role in the pathogenesis and progression of liver fibrosis. Silent information regulator 1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD+) dependent enzyme and responsible for deacetylating the proteins. Increasing numbers of reports have shown that the molecular mechanism of SIRT1 as an effective therapeutic target for liver fibrosis but the transformation is not very clear. In the present study, liver fibrotic tissues were screened by staining with Masson, hematoxylin-eosin staining (H&E) and Immunohistochemistry (IHC) for histopathological observation from the liver biopsy of seventy-seven rhesus monkey, which fixed with 4% paraformaldehyde (PFA) after treatment with high-fat diet (HFD) for two years. And the liver function was further determined by serum biochemical tests. The mRNA levels and protein expression of rat hepatic stellate (HSC-T6) cells were determined after treatment with Resveratrol (RSV) and Nicotinamide (NAM), respectively. The results showed that with the increasing of hepatic fibrosis in rhesus monkeys, the liver function impaired, and the transforming growth factor-ß1 (TGF-ß1), p-Smad3 (p-Smad3) and alpha-smooth muscle actin (α-SMA) was up-regulated, while SIRT1 and Smad7 were down-regulated. Moreover, when stimulated the HSC-T6 with RSV to activate SIRT1 for 6, 12, and 24 h, the results showed that RSV promoted the expression of smad7, while the expression of TGF-ß1, p-Smad3 and α-SMA were inhibited. In contrast, when the cells stimulated with NAM to inhibit SIRT1 for 6, 12, and 24 h, the Smad7 expression was decreased, while TGF-ß1, p-Smad3, and α-SMA expressions were increased. These results indicate that SIRT1 acts as an important protective factor for liver fibrosis, which may be attributed to inhibiting the signaling pathway of TGF-ß/Smad in hepatic fibrosis of the rhesus monkey.

Carbonic Anhydrase 3 is required for cardiac repair post myocardial infarction via Smad7-Smad2/3 signaling pathway.

Appropriate fibrosis is required to prevent subsequent adverse remodeling and heart failure post myocardial infarction (MI), and cardiac fibroblasts (CFs) play a critical role during the process. Carbonic anhydrase 3 (CAR3) is an important mediator in multiple biological processes besides its CO2 hydration activity; however, the role and underlying mechanism of CAR3 on cardiac repair post MI injury remains unknown. Here, we found that CAR3 expression was up-regulated in cardiac tissue in infarct area at the reparative phase of MI, with a peak at 7 days post MI. The upregulation was detected mainly on fibroblast instead of cardiomyocyte, and primary cardiac fibroblasts treated with TGF-ß1 recaptured our observation. While CAR3 deficiency leads to weakened collagen density, enlarged infarct size and aggravated cardiac dysfunction post-MI. In fibroblast, we observed that CAR3 deficiency restrains collagen synthesis, cell migration and gel contraction of cardiac fibroblasts, whereas overexpression of CAR3 in CFs improves wound healing and cardiac fibroblast activation. Mechanistically, CAR3 stabilizes Smad7 protein via modulating its acetylation, which dampens phosphorylation of Smad2 and Smad3, thus inhibiting fibroblast transformation. In contrast, inhibition of Smad7 acetylation with C646 blunts CAR3 deficiency induced suppression of fibroblast activation and impaired cardiac healing. Our data demonstrate a protective role of CAR3 in cardiac wound repair post MI via promoting fibroblasts activation through Smad7-TGF-ß/Smad2/3 signaling pathway.

TRAF2 decrease promotes the TGF-ß-mTORC1 signal in MAFLD-HCC through enhancing AXIN1-mediated Smad7 degradation.

According to recent research, metabolic-associated fatty liver disease (MAFLD) has emerged as an important underlying etiology of hepatocellular carcinoma (HCC). However, the molecular mechanism of MAFLD-HCC is still unclear. Tumor necrosis factor receptor-associated factor 2 (TRAF2) is the key molecule to mediate the signal of inflammatory NF-κB pathway. This study aims to investigate the potential dysregulation of TRAF2 and its biological function in MAFLD-HCC. Huh7 TRAF2-/- demonstrated increased tumor formation ability compared to huh7 TRAF2+/+ when stimulated with transforming growth factor-ß (TGF-ß). The decisive role of TGF-ß in the development of MAFLD-HCC was confirmed through the specific depletion of TGF-ß receptor II gene in the hepatocytes (Tgfbr2ΔHep) of mice. In TRAF2-/- cells treated with TGF-ß, both the glycolysis rate and lipid synthesis were enhanced. We proved the signal of the mechanistic target of rapamycin complex 1 (mTORC1) could be activated in the presence of TGF-ß, and was enhanced in TRAF2-/- cells. The coimmunoprecipitation (co-IP) experiments revealed that TRAF2 fortified the Smurf2-mediated ubiquitination degradation of AXIN1. Hence, TRAF2 depletion resulted in increased Smad7 degradation induced by AXIN1, thus promoting the TGF-ß signal. We also discovered that PLX-4720 could bind with AXIN1 and restrained the tumor proliferation of TRAF2-/- in mice fed with high-fat diet (HFD). Our findings indicate that TRAF2 plays a significant role in the pathogenesis of MAFLD-HCC. The reduction of TRAF2 expression leads to the enhancement of the TGF-ß-mTORC1 pathway by facilitating AXIN1-mediated Smad7 degradation.

Expression of SMADs in orthotopic human endometrium, ovarian endometriosis, and endometriotic lesions in a murine model.

Activin A promotes the development of endometriotic lesions in a murine model of endometriosis, and the immunohistochemical localization of phosphorylated suppressor of mothers against decapentaplegic homolog 2/3 (pSMAD2/3) complex in endometriotic lesions has been reported. Activin may therefore be involved in the development and proliferation of endometriotic cells via the SMAD signaling pathway. However, few detailed reports exist on SMAD7 expression in endometriosis. The purpose of this study was to investigate the expression of pSMAD2/3 or pSMAD3 and SMAD7 in the orthotopic human endometrium, ovarian endometriosis, and endometriotic lesions in a murine model and the effect of activin A on pSMAD2/3 and SMAD7 expression. We established an endometriosis murine model via the intraperitoneal administration of endometrial tissue and blood from donor mice. Activin A was intraperitoneally administered to the activin group. We immunohistochemically evaluated orthotopic endometria, ovarian endometriotic tissues, and endometriotic lesions in the murine model followed by western blotting. We found that pSMAD3 and SMAD7 were expressed in ovarian endometriosis and orthotopic endometria from patients with and without endometriosis. In the murine model, endometriotic lesions expressed pSMAD2/3 and SMAD7 in the activin and control groups, and higher SMAD7 expression was found in the activin group. To the best of our knowledge, this study is the first to show that SMAD7 expression is upregulated in endometriosis. In conclusion, these results suggest that activin A activates the SMAD signaling pathway and promotes the development of endometriotic lesions, thus identifying SMAD7 as a potential therapeutic target for endometriosis.

Leech extract alleviates idiopathic pulmonary fibrosis by TGF-ß1/Smad3 signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Leech, as a traditional Chinese medicine for the treatment of blood circulation and blood stasis, was also widely used to cure pulmonary fibrosis in China. In clinical practice, some traditional Chinese medicine preparation such as Shui Zhi Xuan Bi Hua Xian Tang and Shui Zhi Tong Luo Capsule composed of leech, could improve the clinical symptoms and pulmonary function in patients with idiopathic pulmonary fibrosis (IPF). However, the material basis of the leech in the treatment of IPF were not yet clear. AIM OF THE STUDY: Screen out the components of leech that have the anti-pulmonary fibrosis effects, and further explore the therapeutic mechanism of the active components. MATERIALS AND METHODS: In this study, the different molecular weight components of leech extract samples were prepared using the semi-permeable membranes with different pore sizes. The therapeutic effects of the leech extract groups with molecular weight greater than 10 KDa (>10 KDa group), between 3 KDa and 10 KDa (3-10 KDa group), and less than 3 KDa (<3 KDa group) on pulmonary fibrosis were firstly investigated by cell proliferation and cytotoxicity assay (MTT), cell wound healing assay, immunofluorescence staining (IF) and Western blot (WB) assay through the TGF-ß1-induced fibroblast cell model. Then bleomycin-induced pulmonary fibrosis (BML-induced PF) mouse model was constructed to investigate the pharmacological activities of the active component group of leech extract in vivo. Pathological changes of the mouse lung were observed by hematoxylin-eosin staining (H&E) and Masson's trichrome staining (Masson). The hydroxyproline (HYP) content of lung tissues was quantified by HYP detection kit. The levels of extracellular matrix-related fibronectin (FN) and collagen type Ⅰ (Collagen Ⅰ), pyruvate kinase M2 (PKM2) monomer and Smad7 protein were determined via WB method. PKM2 and Smad7 protein were further characterized by IF assays. RESULTS: Using TGF-ß1-induced HFL1 cell line as a PF cell model, the in vitro results demonstrated that the >10 KDa group could significantly inhibited the cell proliferation and migration, downregulated the expression level of cytoskeletal protein vimentin and α-smooth muscle actin (α-SMA), and reduced the deposition of FN and Collagen Ⅰ. In the BML-induced PF mouse model, the >10 KDa group significantly reduced the content of HYP, downregulated the expression levels of FN and Collagen Ⅰ in lung tissues, and delayed the pathological changes of lung tissue structure. The results of WB and IF assays further indicated that the >10 KDa group could up-regulate the expression level of PKM2 monomer and Smad7 protein in the cellular level, thereby delaying the progression of pulmonary fibrosis. CONCLUSIONS: Our study revealed that the >10 KDa group was the main material basis of the leech extract that inhibited pulmonary fibrosis through TGF-ß1/Smad3 signaling pathway.

SMAD7 expression in CAR-T cells improves persistence and safety for solid tumors.

Despite the tremendous progress of chimeric antigen receptor T (CAR-T) cell therapy in hematological malignancies, their application in solid tumors has been limited largely due to T-cell exhaustion in the tumor microenvironment (TME) and systemic toxicity caused by excessive cytokine release. As a key regulator of the immunosuppressive TME, TGF-ß promotes cytokine synthesis via the NF-κB pathway. Here, we coexpressed SMAD7, a suppressor of TGF-ß signaling, with a HER2-targeted CAR in engineered T cells. These novel CAR-T cells displayed high cytolytic efficacy and were resistant to TGF-ß-triggered exhaustion, which enabled sustained tumoricidal capacity after continuous antigen exposure. Moreover, SMAD7 substantially reduced the production of inflammatory cytokines by antigen-primed CAR-T cells. Mechanistically, SMAD7 downregulated TGF-ß receptor I and abrogated the interplay between the TGF-ß and NF-κB pathways in CAR-T cells. As a result, these CAR-T cells persistently inhibited tumor growth and promoted the survival of tumor-challenged mice regardless of the hostile tumor microenvironment caused by a high concentration of TGF-ß. SMAD7 coexpression also enhanced CAR-T-cell infiltration and persistent activation in patient-derived tumor organoids. Therefore, our study demonstrated the feasibility of SMAD7 coexpression as a novel approach to improve the efficacy and safety of CAR-T-cell therapy for solid tumors.

Circular RNA circWNK1 inhibits the progression of gastric cancer via regulating the miR-21-3p/SMAD7 axis.

Gastric cancer (GC) is a highly aggressive malignancy with limited treatment options for advanced-stage patients. Recent studies have highlighted the role of circular RNA (circRNA) as a novel regulator of cancer progression in various malignancies. However, the underlying mechanisms by which circRNA contributes to the development and progression of GC remain poorly understood. In this study, we utilized microarrays and real-time quantitative polymerase chain reaction (qRT-PCR) to identify and validate a downregulated circRNA, hsa_circ_0003251 (referred to as circWNK1), in paired GC and normal tissues. Through a series of in vitro and in vivo gain-of-function and loss-of-function assays, we demonstrated that circWNK1 exerts inhibitory effects on the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of GC cells. Additionally, we discovered that circWNK1 acts as a competitive endogenous RNA (ceRNA) for SMAD7 by sequestering miR-21-3p. Our findings were supported by comprehensive biological information analysis, as well as RNA pull-down, luciferase reporter gene, and western blot assays. Notably, the downregulation of circWNK1 in GC cells resulted in reduced SMAD7 expression, subsequently activating the TGF-ß signaling pathway. Collectively, our study reveals that circWNK1 functions as a tumor suppressor in GC by regulating the miR-21-3p/SMAD7-mediated TGF-ß signaling pathway. Furthermore, circWNK1 holds promise as a potential biomarker for the diagnosis and treatment of GC.

TGF-ß1 signaling and Smad7 control T-cell responses in health and immune-mediated disorders.

Transforming growth factor (TGF)-ß1, a member of the TGF-ß superfamily, is produced by many immune and nonimmune cells and has pleiotropic effects on both innate and adaptive immunity, especially in the control of T-cell differentiation and function. Consistently, loss of TGF-ß1 function is associated with exacerbated T-cell-dependent inflammatory responses that culminate in pathological processes in allergic and immune-mediated diseases. In this review, we highlight the roles of TGF-ß1 in immunity, focusing mainly on its ability to promote differentiation of regulatory T cells, T helper (Th)-17, and Th9 cells, thus contributing to amplifying or restricting T-cell responses in health and human diseases (e.g., inflammatory bowel diseases, type 1 diabetes, asthma, and MS). In addition, we discuss the involvement of Smad7, an inhibitor of TGF-ß1 signaling, in immune-mediated disorders (e.g., psoriasis, rheumatoid arthritis, MS, and inflammatory bowel diseases), as well as the discordant results of clinical trials with mongersen, an oral pharmaceutical compound containing a Smad7 antisense oligonucleotide, in patients with Crohn's disease. Further work is needed to ascertain the reasons for such a discrepancy as well as to identify better candidates for treatment with Smad7 inhibitors.

Hydronidone ameliorates liver fibrosis by inhibiting activation of hepatic stellate cells via Smad7-mediated degradation of TGFßRI.

BACKGROUND AND PURPOSE: Liver fibrosis is a wound-healing reaction that eventually leads to cirrhosis. Hydronidone is a new pyridine derivative with the potential to treat liver fibrosis. In this study, we explored the antifibrotic effects of hydronidone and its potential mode of action. METHODS: The anti-hepatic fibrosis effects of hydronidone were studied in carbon tetrachloride (CCl4 )- and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)- induced animal liver fibrosis. The antifibrotic mechanisms of hydronidone were investigated in hepatic stellate cells (HSCs). The antifibrotic effect of hydronidone was further tested after Smad7 knockdown in HSCs in mouse models of fibrosis. RESULTS: In animal models, hydronidone attenuated liver damage and collagen accumulation, and reduced the expression of fibrosis-related genes. Hydronidone decreased the expression of fibrotic genes in HSCs. Impressively, hydronidone significantly upregulated Smad7 expression and promoted the degradation of transforming growth factor ß receptor I (TGFßRI) in HSCs and thus inhibited the TGFß-Smad signalling pathway. Specific knockdown of Smad7 in HSCs in vivo blocked the antifibrotic effect of hydronidone. CONCLUSION: Hydronidone ameliorates liver fibrosis by inhibiting HSCs activation via Smad7-mediated TGFßRI degradation. Hydronidone is a potential drug candidate for the treatment of liver fibrosis.

Overexpression of SMAD7 improves the function of EGFR-targeted human CAR-T cells against non-small-cell lung cancer.

BACKGROUND AND OBJECTIVE: Recent advancements in immunotherapy led to the development of Chimeric antigen receptor (CAR) T-cell therapy. CAR-T cell therapy in non-small cell lung cancer (NSCLC) is hindered by overexpression of transforming growth factor (TGFß) in the cancer cells that have a negative regulatory role on T-cells activity. This study characterized CAR-T with overexpression of mothers against decapentaplegic homologue 7 (SMAD), a negative regulator of TGFß downstream signalling. METHODS: We have generated three types of CAR-T: epidermal growth factor receptor (EGFR)-CAR-T, EGFR-dominant-negative TGFbeta receptor 2 (DNR)-CAR-T, and EGFR-SMAD7-CAR-T by transducing human T-cells with the lentivirus constructs. We characterized the proliferation, expression of proinflammatory cytokines, activation profile, and lysis capacity in co-cultures with A549 lung carcinoma cells with and without TGFß neutralizing antibodies. We also tested the therapeutic potential of EGFR-SMAD7-CAR-T in the A549 cells tumour-bearing mice model. RESULTS: Both EGFR-DNR-CAR-T and EGFR-SMAD7-CAR-T demonstrated a higher proliferation rate and lysis capacity to A549 than traditional EGFR-CAR-T. Neutralization of TGFß by the antibodies resulted in increased performance of EGFR-CAR-T. In vivo, both EGFR-DNR-CAR-T and EGFR-SMAD7-CAR-T resulted in complete tumour resorption by day 20, whereas conventional CAR-T only has a partial effect. CONCLUSION: We demonstrated the high efficacy and resistance to negative TGFß regulation of EGFR-SMAD7-CAR-T comparable with EGFR-DNR-CAR-T and without the systemic effect of TGFß inhibition.

Aloe-emodin ameliorated MI-induced cardiac remodeling in mice via inhibiting TGF-ß/SMAD signaling via up-regulating SMAD7.

BACKGROUND: Aloe-emodin (AE), a natural anthraquinone extract from traditional Chinese medicinal plants, has been certified to protect against acute myocardial ischemia. However, its effect on cardiac remodeling after chronic myocardial infarction (MI) and the possible mechanism remain unclear. PURPOSE: This study investigated the effect of AE on cardiac remodeling and oxidative damage induced by myocardial infarction (MI) in vitro and explored the underlying mechanisms. METHODS: Echocardiography and Masson staining were used to demonstrate myocardial dysfunction and fibrosis. Cell apoptosis was detected by TUNEL staining. The expressions of fibrosis-related factors such as type I collagen, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) were detected by Western blot. RESULTS: Our data demonstrated that AE treatment significantly improved cardiac function, reduced structural remodeling, and reduced cardiac apoptosis and oxidative stress in mice with myocardial infarction. In vitro, AE could protect neonatal mouse cardiomyocytes (NMCM) from angiotensin II (Ang II)-induced cardiomyocyte hypertrophy and apoptosis, and significantly inhibited (p < 0.05) Ang II-induced reactive oxygen species (ROS) increase. Furthermore, AE treatment significantly reversed the Ang ii-induced upregulation. CONCLUSION: In summary, our work reveals for the first time that AE activates the TGF-ß signaling pathway by up-regulating Smad7 expression, which in turn regulates the expression of fibrosis-related genes, ultimately improving cardiac function, inhibiting the development of cardiac fibrosis and hypertrophy in rats with chronic MI.

miR-181c targets Parkin and SMAD7 in human cardiac fibroblasts: Validation of differential microRNA expression in patients with diabetes and heart failure with preserved ejection fraction.

BACKGROUND: Cardiac fibrosis represents a key element in the pathophysiology of heart failure with preserved ejection fraction (HFpEF), a condition highly prevalent amongst geriatric patients, especially if diabetic. The microRNA 181c (miR-181c) has been shown to be associated with the response to exercise training in HFpEF patients and has been also linked to diabetic cardiovascular complications. However, the underlying mechanisms have not been fully elucidated. OBJECTIVE: To measure circulating miR-181c in elderly patients with HFpEF and diabetes mellitus (DM) and identify gene targets pathophysiologically relevant in HFpEF. METHODS: We quantified circulating miR-181c in frail older adults with a confirmed diagnosis of HFpEF and DM, and, as control, we enrolled age-matched subjects without HFpEF and without DM. We validated in human cardiac fibroblasts the molecular mechanisms linking miR-181c to a pro-fibrotic response. RESULTS: 51 frail patients were included :34 patients with DM and HFpEF and 17 age-matched controls. We observed that miR-181c was significantly upregulated (p < 0.0001) in HFpEF patients vs controls. We confirmed in vitro that miR-181c is targeting PRKN and SMAD7. CONCLUSIONS: We demonstrate that miR-181c levels are significantly increased in frail elderly adults with DM and HFpEF and that miR-181c targets PRKN and SMAD7 in human cardiac fibroblasts.

Rebalancing SMAD7/SMAD3 Signaling Reduces Adhesion Formation during Flexor Tendon Healing.

Transforming growth factor-ß is a key factor in regulating adhesion formation during tendon healing. We investigated the effectiveness of SMAD family members, SMAD7 and SMAD3, in the TGF-ß/Smad signaling during flexor tendon repair. Mouse flexor toe deep tendon rupture anastomosis models were made. On days 3, 7, 14, 21, and 28, the expressions of smad7 and smad3 in flexor tendon tissues were detected by RT-qPCR and western blot. Furthermore, postoperative intraperitoneal injections of SMAD7 agonists or SMAD3 antagonists were given. The degree of tendon healing was evaluated by adhesion testing and biomechanical experiments. Hematoxylin and eosin (HE) staining was used to observe the pathological changes. Immunohistochemistry was used to evaluate the expressions of collagen III, SMAD3, and SMAD7. The mRNA levels of matrix metalloproteinases, Mmp2 and Mmp9, and scleraxis (SCX) in flexor tendon tissue were detected by RT-qPCR. Smad3 expression increased and Smad7 expression decreased in flexor tendon tissue after injury. In addition, the SMAD7 agonist blocked SMAD3 phosphorylation. SMAD7 agonist and SMAD3 antagonist both improved adhesion formation during flexor tendon healing, and decreased the expressions of collagen III, Mmp9, and SCX, while increasing Mmp2 expression. This study provides a possible theoretical basis for the SMAD7-SMAD3 signal cascade during flexor tendon adhesion healing.

HIF-1α-induced upregulated miR-322 forms a feedback loop by targeting Smurf2 and Smad7 to activate Smad3/ß-catenin/HIF-1α, thereby improving myocardial ischemia-reperfusion injury.

Myocardial ischemia/reperfusion injury (MIRI) is a major cause of heart failure after myocardial infarction. It has been reported that miR-322 is involved in MIRI progression, while the molecular mechanism of miR-322 in regulating MIRI progression needs to be further probed. MIRI cell model was established by oxygen-glucose deprivation/reoxygenation (OGD/R). Cell viability was assessed using MTS assay. Flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining were employed to analyze cell apoptosis. In addition, the interactions between miR-322, Smad7/Smurf2, hypoxia-inducible factor alpha (HIF-1α), and ß-catenin were verified by dual-luciferase reporter gene assay. Our results displayed that miR-322 was significantly downregulated in OGD/R-treated H9c2 cells, and its overexpression resulted in increased cell viability and reduced the apoptosis. Smurf2 and Smad7 were identified as the direct targets of miR-322. Smad7 knockdown or Smurf2 knockdown increased OGD/R-treated H9c2 cell viability and suppressed the apoptosis. Meanwhile, miR-322 mimics abolished the mitigating effect of Smad7 or Smurf2 overexpression on MIRI. In addition, the Smad3/ß-catenin pathway was identified as the downstream pathway of Smurf2/Smad7. Moreover, it was found that HIF-1α interacted with the miR-322 promoter, and ß-catenin interacted with the HIF-1α promoter to form a loop. HIF-1α-induced upregulated miR-322 activated the Smad3/ß-catenin pathway by targeting Smurf2 and Smad7 to improve MIRI; meanwhile, ß-catenin/HIF-1α formed a positive feedback loop to continuously improve MIRI.

Exosomal miR-21-5p derived from multiple myeloma cells promote renal epithelial-mesenchymal transition through targeting TGF-ß/SMAD7 signalling pathway.

The prognosis of multiple myeloma (MM) patients combined with renal insufficiency is poor. Renal fibrosis is an important pathological cause for MM patients combined with renal insufficiency. It is reported that epithelial-mesenchymal transition (EMT) of renal proximal tubular epithelial cells is an important mechanism in renal fibrosis. We speculated that EMT might play an important role in the renal insufficiency of MM with unclear mechanism. MM cells derived exosomes could affect the function of targeted cells by delivering microRNAs (miRNAs). Literature has shown that the expression of miR-21 is closely related to EMT. In this research, we found that co-culture of HK-2 cells (human renal proximal tubular epithelial cells) and exosomes derived from MM cells promoted the EMT of HK-2 cells, resulting in the down-regulation of epithelial-related marker (E-cadherin), and up-regulation of stroma-related marker (Vimentin). Meanwhile, the expression of SMAD7, one of the downstream targets in the TGF-ß signalling pathway, was suppressed and the expression of TGF-ß was increased. After transfecting the inhibitor of miR-21 in MM cells, the expression of miR-21 in exosomes secreted by MM cells was significantly decreased, and the co-culture of these treated exosomes and HK-2 cells inhibited the EMT of HK-2 cells. In conclusion, these findings showed that exosomal miR-21 derived from MM cells could promote renal EMT through targeting TGF-ß/SMAD7 signalling pathway.

Glycyrrhizic acid alleviates liver fibrosis in vitro and in vivo via activating CUGBP1-mediated IFN-γ/STAT1/Smad7 pathway.

BACKGROUND: Hepatic fibrosis, a common pathological feature of chronic liver injuries, is a serious public health problem and lacks effective therapy. Glycyrrhizic acid (GA) is a bioactive ingredient in the root of traditional Chinese medicine licorice, and exhibits remarkable anti-viral, anti-inflammatory and hepatoprotective actions. PURPOSE: Here we aimed to investigated whether GA provided a therapeutic efficacy in hepatic fibrosis and uncover its molecular mechanisms. STUDY DESIGN AND METHODS: We investigated the anti-fibrosis effects of GA using CCl4-induced mouse mode of liver fibrosis as well as TGF-ß1-activated human LX-2 cells and primary hepatic stellate cells (HSCs). CUGBP1-mediated IFN-γ/STAT1/Smad7 signaling was examined with immunofluorescence staining and western blot analysis. We designed and studied the binding of GA to CUGBP1 using in silico docking, and validated by microscale thermophoresis (MST) assay. RESULTS: GA obviously attenuated CCl4-induced liver histological damage, and reduced serum ALT and AST levels. Meanwhile, GA decreased liver fibrogenesis markers such as α-SMA, collagen α1, HA, COL-III, and LN in the hepatic tissues. Mechanistically, GA remarkably elevated the levels of IFN-γ, p-STAT1, Smad7, and decreased CUGBP1 in vivo and in vitro. Over-expression of CUGBP1 completely abolished the anti-fibrotic effect of GA and regulation on IFN-γ/STAT1/Smad7 pathway in LX-2 cells and primary HSCs, confirming CUGBP1 played a pivotal role in the protection by GA from liver fibrosis. Further molecular docking and MST assay indicated that GA had a good binding affinity with the CUGBP1 protein. The dissociation constant (Kd) of GA and CUGBP1 was 0.293 µM. CONCLUSION: Our study demonstrated for the first time that GA attenuated liver fibrosis and hepatic stellate cell activation by promoting CUGBP1-mediated IFN-γ/STAT1/Smad7 signalling pathways. GA may be a potential candidate compound for preventing or reliving liver fibrosis.

Genetic analysis and allele-specific expression of SMAD7 3'UTR variants in human colorectal cancer reveal a novel somatic variant exhibiting allelic imbalance.

BACKGROUND: Considering the impact of SMAD7 deregulation in colorectal cancer (CRC) progression and the significance of single nucleotide variant (SNV)-mediated disruptions of microRNA (miRNA)-dependent regulation for cancer susceptibility, our study aimed to analyze genetic variation in the SMAD7 3' untranslated region ( 3'UTR) in CRC, measure differences in allelic mRNA expression, and evaluate its interference with miRNA-mediated post-transcriptional regulation. PATIENTS AND METHODS: This study included 80 patients with different CRC stages and six human colon cancer cell lines of various histological origins. SMAD7 3'UTR was analyzed by direct sequencing, followed by the relative quantification of differential allelic expression of detected variants by allele-specific qRT-PCR. In silico tools were employed for predictions of regulatory consequences of detected variants. RESULTS: A total of four different SNVs in one cell line and nine patients were found, among which were a novel somatic point variant and three already known germline variants (rs16950113, rs1050799536, and rs1043778717). All evaluated SNVs exhibited variable extents of allelic imbalance in expression. In silico analysis predicted significant effects of SNVs on miRNA binding efficiency, with each SNV disrupting existing and creating new target sites for one or more miRNAs. CONCLUSION: Imbalance observed in the expression of SNV alleles altering miRNA binding suggests that all investigated SNVs are potential contributing factors impacting SMAD7 expression regulation in CRC that further studies should investigate.

Monocyte-derived immature dendritic cells negatively regulate hepatic stellate cells in vitro by secreting IL-10.

The development of liver fibrosis is associated with inflammatory responses resulting from chronic liver disease. Immature dendritic cells (imDCs) play an important role in modulating the inflammatory environment of the liver. This study investigated the effects of imDCs on the regulation of hepatic stellate cells (HSCs) during liver fibrosis. We isolated and induced imDCs from monocytes of healthy volunteers, activated LX-2 cells with TGF-ß to establish in vivo liver fibrosis HSCs model, and then set up a cell co-culture system with transwell membranes. imDC surface markers and apoptosis rates of LX-2 cells were detected by flow cytometry. The concentration of IL-10 secreted by imDC was measured through ELISA. The expression of α-SMA in LX-2 after co-culture was examined by qRT­PCR. Proliferation of LX-2 cells were detected by CCK-8. The western blot was used to illustrate the LX-2 activation-related proteins such as Smad3/7 and TGF-ß1. The imDCs co-culture group and the interleukin-10 (IL-10) treatment group had similar results, as they were both able to increase apoptosis, inhibit proliferation, downregulate α-SMA mRNA, and reduce TGF-ß1 and Smad3 protein expression in LX-2 cells. Additionally, the Smad7 protein level was increased after treatment with imDC and IL-10. However, the results in the IL-10 antagonist group showed the opposite trend to that of imDCs and IL-10 groups. Thus, these results suggest that imDC secretion of IL-10 negatively regulates activated LX-2 cells, probably via inhibition of the TGF-ß1/Smad3 pathway and increased expression of Smad7 protein. This may be a potential therapeutic target for liver fibrosis.